Safety switch and resetting mechanism therefor



1950 5. H. BROWN 2,519,432

SAFETY SWITCH AND RESETTING MECHANISM THEREFOR Filed Feb. 16, 1945 2 Sheets-Sheet l "47/ M W /M' 1N VEN TOR. 6&fa a/7 /7, Bra Wrz 2, 1950 e. H. BROWN 2,519,432

SAFETY swmcn AND RESETTING MECHANISM THEREFOR Filed Feb. 16, 1945 2 Sheets-Sheet 2 E. E INVENTOR.

l7 T7017 NE X Patented Aug. 22, 1950 SAFETY SWITCH AND RESETTING MECHANISM THEREFOR Gordon H. Brown, Detroit, Mich. Application February 16, 1945, Serial No. 578,137

1 11 Claim. This invention relates to a safety switch and resetting mechanism therefor.

Principal objects of the invention are to provide:

A new and improved safety switch and resetting mechanism for electric teakettles and applicances of a similar nature; 7

A thermostatic safety switch which can be reset by pushing the current conducting plug attached to the current connectors on a heated device thereagainst;

A thermostatic safety switch having simple and easily operable means for resetting such switch.

Other and further objects of the invention will be apparent from the following description and claims and will be understood by reference to the accompanying drawings, of which there are two sheets, which, by way of illustration, show preferred embodiments and the principles thereof and what I now consider to be the best mode in which I have contemplated applying those principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by them skilled in the art without departing from "the present invention and the purview of the appended claims.

I also contemplate that of the several different features of my invention, certain ones thereof may be advantageously employed in some applications separate and apart from the remainder of the features.

In the drawings:

Fig. 1 is a side elevational view of an electric teakettle embodying the invention, certain of v Fig. 5 is a fragmentary front elevational view,

with certain parts of the handle and shell broken away;

Fig. 6 is a fragmentary rear elevational view;

Fig. '7 is an enlarged vertical sectional view through the thermostatic safety switch and resetting mechanism but with some of the parts shown in elevation;

Fig. 8 is a schematic view illustrating the wiring diagram;

Fig. 9 is a view similar to Fig. 3 but illustrating a modified form of the invention; and

Fig. 10 is a perspective view of certain of the parts of the manually operable resetting mechanism for the thermostatic safety switch illustrated in Fig. 9.

An electric teakettle embodying theinvention may comprise a shell 10 having a heating element l2 therein a cover H, a handle I, and thermostatic safety switch and resetting mechanism which is partially illustrated in Figs. 8 and 4.

The shell it may be formed to provide a vessel which may be of generally oval shape for bolding water, and a pouring and filling spout 20. The cover H preferably is secured removably to the rim of the shell.

The cover it may be formed of a die casting of aluminum or other suitable material and is assembled on the shell in such a manner as to close the top of the same except for the opening provided by the spout Ill.

The handle i8, which may be formed of plastic or other suitable material, at its front is secured to the cover by a bolt 38 and at its rear by two bolts 40. As the heads of the bolts 3| and I! are on the under side of the cover II. the handle it must be assembled to the cover I before the same is assembled to the shell II. In addition, all of the apparatus or mechanism is assembled to the cover l4, and such assembly must take place before the cover It is secured to the shell Ill. The rear of the handle is enlarged to form a cavity which cooperates with a suitable depression or recess formed in the cover H at the rear thereof to provide an enclosure or housing for the thermostatic safety switch and resetting mechanism.

The cover M below the aforementioned cavity at the back thereof is formed to provide a depending part 44 upon which the heating element I2 is mounted. Such part 44 includes a pair of sockets 46 in which the ends of the heating element 12 are secured. The heating element may comprise an electric resistance heating element of the type in which an electric resistance is embedded in a refractory insulation encased in a tube or sheath. The heating element i2 is arranged in the form of a loop which is arranged adjacent the bottom of the shell Hi. The upper ends of the sockets are threadedto receive nuts 48 which cooperate with packing in the sockets 48 and the ends of the element H for securing the same in place. Between the sockets 46 a well 50 is formed in the depending part 44. The bimetallic element 52 of a thermostatic safety switch has its lower end embedded in a mass of metal 54 disposed in the bottom of well 88. An insulating block or panel 56 is mounted at the front of the recess and on the cover I4 by bolts 58, and this insulating block 56 has mounted thereon spring mounted contacts 68 and 62, each of the contacts being carried by a strip which is bolted by a bolt and nut assembly 64 to the block 56. The upper end of the bimetallic element 52 is in the form of a cross and includes laterally extending arms 66. A lever assembly 68 is mounted on the upper knife edge of the part 18 of the bimetallic element 52 which projects above the arms 66. The lever assembly 68 includes a U- shaped lower end, the legs 12 and I4 of which straddle the part I8 as illustrated in Fig. 3.

A lining (not shown) may be arranged inside the U-shaped lower end of the lever assembly 68 so that the latter is free to-rock or slide upon the knife edge which is provided on the top of the upper end I8 of the bimetallic element, and suitable means may be employed to keep the lever assembly 68 in placeon the upper edge of element 52.

The upper end of the lever assembly has universally mounted thereon a bridge I6 which bridges the contacts 68 and 62 when the parts are arranged as illustrated in Figs. 3 and 4. In

I this position the circuit through the heating elebimetallic element 52. During normal operation the bimetallic element 52 and lever 68 are in the position illustrated. However, when the temperof the bimetallic element 52 will move to the left (Fig. 3) sufficiently to throw the upper end of the lever 68 to the right sufiiciently to move the bridge I6 so as to open the switch.

The lever 68 includes laterally extending arms 88. Springs 82 connected to the arms 88 of the lever 68 and the arms 66 of the bimetallic element 52 bias the bridge 16 either towards or away from the contacts 68 and 62. As the bimetallic element 52 heats up, the upper end 18 thereof moves gradually to the left (Fig. 3) and as soon as the arms 88 of the lever 68 move to the right past the knife edge on the upper end I8 of the bimetallic element, the springs 82 will snap the lever to the right thereby rapidly opening the switch. For the sake of clarity, the springs 82 are omitted from Fig. 3.

In order to close the switch it is necessary to reset the same, and this is accomplished in the following manner and with the use of the following resetting mechanism. A plate 84 mounted by bolts 86 on the cover I4 is turned up at one end to provide a wall 88 which has rigidlymounted thereon two rearwardly extending pins .88. The pins 88 extend through guide holes in a a plate 82. Plate 82 has securely mounted thereon handle limit the movement of the plate 92. Thus the plate 52 is mounted on the wall 88 and for reciprocating movement relative thereto by the pins 88 and 84.

The plate 82 carries prongs forming terminal connectors I82 which are adapted to fit within the terminal sockets carried by a conventional Plug I84 on the end of a current conductor. The enclosure formed by the cover I4 and the handle I6 which encloses the thermostatic safety switch and resetting mechanism is open at the back so that such plug may be operatively associated with the terminals I82 which through the thermostatic safety switch are operatively connected with the heating element I2.

The pin 94 is adapted to contact the lever 68, when the thermostatic safety switch is open, for resetting the same. This resetting operation is accomplished when the plug I84 is mounted on the terminals I82 by pushing the plug forwardly or to the left, looking at Figs. 3 and 4. This causes a forward movement of the plate 92 and pin 84 which will engage the lever 68 if the switch is open and push it past the center of the toggle for closing the safety switch, provided that the 4 I video with a threaded hole with which a screw H2 is cooperable for removably securing in place the terminal shroud I I4 which conceals the joint between the handle and the shell in at the rear of the kettle. The shroud H4 is shaped to fit the edges of the handle and the back of the shell and has an opening for the plug I84 and through which the terminals I82 project.

The leads between the various terminals have been omitted for the sake of clarity, but the cir-' cult is indicated in Fig. 8 wherein it appears that one of the terminals I82 is connected to a terminal I88 for the contact 62. The other terminal I82 is connected to a terminal I32 .01? one end of the heating element I2 while the other terminal I84 of the heating element I2 is connected to the terminal for the switch contact 68.

A signal light I86 comprising the usual high resistance filament may be connected across the terminals of the switch contacts 68 and 62 and arranged-so that when such contacts are open the signal will be illuminated. The signal may be mounted above the panel 56 and be visible through a window I38 arranged in the handle I6 above the light I36.

In the modified form of reset mechanism illustrated in Figs. 9 and 18, the terminals I82 are mounted on a bracket 288 which is suitably secured and fixed to the bottom wall 282 of the cavity which houses the thermostat and reset mechanism. A bracket 284, illustrated in Fig. 10, and provided with legs 288, is rockably mounted by means of the legs 286 in suitable sockets formed in the-bracket 288. Springs 288 normally position the bracket 284 as illustrated in Fig. 9.

The bracket carries a rod 2I8, the upper end of which is provided with a push button 2I2 which projects through an opening in the top wall of the cavity. The lower end of the rod 2I8 is seated on a horizontal part 2I4 of the bracket 284 and located relative thereto so that downward pressure on the push button 2I2 will tend to rock the bracket 284 in a. counterclockwise direction (Fig. 9) about its pivotal mounting and against the tension of the spring 288.

The bracket 204 carries a liner I" which is engageable with the lever II when the thermostatic switch is open for shifting the lever I! back to its position as illustrated in Pig. 9 for closing said thermostatic switch provided that the bimetallic element ll thereof has cooled down sufliciently. The thermostatic switch mechanism otherwise is the same as that illustrated in Figs. 1 to 8. After release of the push button 2|: the bracket 204 will return to the position as illustrated in Fig. 9 under the action of springs 208 since each spring is connected to brackets 200 and 2.

This application is a continuation in part of my prior copending application Serial No. 539,201, filed June '7, 1944, for "EiectricTeakettle and Cover Assembly."

While I have illustrated and described preferred embodiments of myinvention, it is understood that these are capable of modification and I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations which fall within the purview of the following claims.

I claim:

1. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit adapted to be removably coupled with a plug of a current conductor,

said switch comprising a plurality of contacts, at least one of which is movable, a thermally responsive element operable by heat from said device for moving said contact to open said circuit, and means engageable with said movable contact and operable by pushing said plug against said connectors for resetting said movable switch contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said means, said terminal connectors and switch being constructed and arranged relative to each other so that the position of said plug on said terminal connectors will not be disturbed by the switch opening movement of said movable contact by said thermally responsive element.

2. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit adapted to be coupled with a plug of a current conductor, said switch comprising a plurality of contacts, at least one of which is movable, a thermostatically operated element for moving said contact to open said circuit, means for movably mounting said terminal connectors, said terminal connectors having a part movable therewith engageable with said movable contact and operable by pushing said plug against said connectors for resetting said movable switch contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said movable part, said terminal connectors and switch being constructed and arranged relative to each other so that the position of said plug on said terminal connectors will not be disturbed by the switch opening movement of said movable contact by said thermally responsive element.

3. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit adapted to be coupled with a plug of a current conductor, said switch comprising a plurality of contacts. at least one 01' which is movable, a thermostatically operated ele- 6 ment for moving said contact to open said circuit, spring means for movably mounting said terminal connectors, said terminal connectors having a part movable therewith engageable with said movable contact and operable by pushing said plug against said connectors for resetting said movable switch contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said movable part, said terminal connectors and switch being constructed and arranged relative to each other so that the position of said plug on said terminal connectors will not be disturbed by the switch opening movement of said movable contact by said thermally responsive element.

4. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit adapted to be removably coupled with a plug of a current conductor. said switch comprising a plurality of contacts, at least one of which movable, a thermally responsive element operable by heat from said device for moving said contact to open said circuit, and means engageable with said movable contact and operable by pushing said plug against said connectors for resetting said movable swich contact to close said switch, the operation oi said thermally responsive element positioning said movable contact for resetting by said means, said terminal connectors and switch being constructed and arranged relative to each other so that the position of said plug on said terminal connectors will not be disturbed by the switch opening movement of said movable contact by said thermally responsive element.

5. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit adapted to be coupled with a plug of a current conductor, said switch comprising a plurality of contacts, at least one of which is movable, a thermally responsive element operable by heat from said device responsive to heat generated by operation of said device for moving said contact to open said circuit, means for movably mounting said terminal connectors, said terminal connectors having a part movable therewith cooperable with said movable contact for resetting the same to close said switch after said thermostatically operated element has cooled down, the operation of said thermally responsive element positioning said movable contact for resetting by said movable part, said terminal connectors and switch being constructed and arranged relative to each other so that the position of said plug on said terminal connectors will not be disturbed by the switch opening movement of said movable contact by said thermally responsive element.

6. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, said switch comprising a stationary contact, a movable contact operable for engaging said stationary contact to close said circuit, a bimetallic element responsive to heat generated by the operation of said device and comprising a lever, a second lever having a bifurcated end, one end of said firstmentioned lever having an edge upon which the bifurcated end of said second lever is rockably arranged, spring means connected to said levers tor biasing said second lever into a position angularly related to said first-mentioned lever and on either side thereoi, movable contact being carried at the other end of said second lever and operable when the bimetallic element is relatively cold for engaging said stationary contact to close said switch, said bimetallic element when subjected to heat resulting from the operation of said device being movable toward said stationary contact so as to cause said second lever to rock on the knife edge thereof suflicient to permit said spring means to move said second lever and contact carried thereby away from said stationary contact to open the switch, said circuit having terminal connectors to which a plug of a current conductor is adapted to be removably coupled, means for movably mounting said terminal connectors on said device, and means operable upon movement of said terminal connectors in one direction for cooperation with one of said levers to reposition the same after said bimetallic element has cooled down for positioning said movable contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said means, said terminal connectors and switch being constructed and arranged relative, to each other so that the position of said plug on said terminal connectors will not be disturbed by the switch opening movement of said movable contact by said thermally responsiveelement.

7. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit, a plug of a current conductor removably coupled to said connectors, said switch comprising a plurality of contacts, at

least one of which is movable, a thermally responsive element operable by heat from said device arranged for moving said contact to open said circuit without disturbing the relationship of said plug and connectors, said element and movable contact being constructed and arranged so that said element is not operable to reengage said contacts to close said circuit, and means engageable with said movable contact and operable by pushing said plug while coupled to said connectors for resetting said movable switch contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said means.

8. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit, a plug of a current conductor removably coupled to said connectors, said switch comprising a plurality of contacts, at least one of which is movable, a thermally responsive element operable by heat from said device arranged for moving said contact to open said circuit without disturbing the relationship of said plug and connectors, and means for movably mounting said terminal connectors, said terminal connectors having a part movable therewith engageable with said movable contact for resetting said movable switch contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said movable part.

9. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit, a plug of a current conductor removably coupled to said connectors, said switch comprising a plurality of contacts, at least one of .which is movable, a thermally responsive element operable by heat from said device arranged for moving said contact to open said circuit without disturbing the relationship of said plug and connectors, and spring means for movably mounting said terminal connectors, said terminal connectors having a part movable'therewith engageable with said movable contact by pushing said plug against said connectors for resetting said movable switch contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said means.

10. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, terminal connectors for said circuit, a plug of a current conductor adapted to be removably coupled to said connectors, said switch comprising a plurality of contacts, at least one of which is movable, a thermally responsive element operable by heat from said device for moving said contact to open said circuit, said element and movable contact being constructed and arranged so that said element is not operable to reengage said contacts to close said circuit as said element cools down, and means engageable with said movable contact and operable by pushing said plug while coupled to said. connectors for resetting said movable switch contact to close said switch, said means being constructed and arranged so that said thermostatic element may open said switch without separating said plug from said terminal connectors, the operation of said thermally responsive element positioning said movable contact for resetting by said means.

11. Safety switch and resetting mechanism for the electric circuit of a heated device comprising a thermostatic switch in said circuit, said switch comprising a stationary contact, a movable contact operable for engaging said stationary contact to close said circuit, a bimetallic element responsive to heat generated by the operation of said device, a lever rockably arranged upon said bimetallic element, spring means connected to said lever for biasing said lever into a position angularly related to said bimetallic element and on either side thereof, said movable contact being carried by said lever and operable when the bimetallic element is relatively cold for engaging said stationary contact to close said switch, said bimetallic element when subjected to heat resulting from the operation of said device being mov able toward said stationary contact so as to cause said lever to rock sufiicient to permit said spring means to move said lever and contact carried thereby away from said stationary contact to open the switch, said circuit having terminal connectors to which a plug of a current conductor is adapted to be removably coupled, means for movably mounting said terminal connectors on said device, and means operable upon movement of said terminal connectors in one direction for cooperation with said lever to reposition the same after said bimetallic element has cooled down for positioning said movable contact to close said switch, the operation of said thermally responsive element positioning said movable contact for resetting by said means, said terminal connectors and switch being constructed and arranged relative to each other so that the position of said plug on said terminal connectors will not be disturbed by the switch opening movement of said movable contact by said thermally responsive element.

GORDON H. BROWN.

(References on following page) REFERENCES CITED The following references are of record in the file of this patent:

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